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Indicator Type: Environmental Condition
Sulphur dioxide (SO2) is a compound formed when fossil fuels, such as coal and natural gas, are burned. This indicator shows trends in annual average concentrations of sulphur dioxide.
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Trend: Mixed Trends
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What does the indicator show?
Annual concentrations of sulphur dioxide have decreased by 6 to 87% at most Alberta stations since 1990, with statistically significant decreases found at Edmonton East (62% decrease), Calgary East (60%), Violet Grove (41%), Tomahawk (36%), Carrot Creek (69%), Fort McMurray – Athabasca Valley (87%), Red Deer (34%) and Fort Saskatchewan (61%). Increasing trends in annual average sulphur dioxide are found in areas north of Fort McMurray (12 to 67%) and at Redwater (45%), however these trends are not statistically significant. The highest average sulphur dioxide concentrations are found at the industrial-influenced stations of the Fort McMurray oilsands region and Redwater.
The indicator shows that Alberta's mean annual objective has not been exceeded from 1990 - 2007. The mean annual objective is 11 parts per billion.
Trends in peak concentrations and exceedances of maximum desirable levels are also available.
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Why is this indicator important?
Sulphur dioxide is a key contributor to acid deposition, including acid rain. When acidic substances like sulphur dioxide are deposited on the earth's surface, they may change the chemical properties of the soil or water. These changes may alter, harm or even destroy soil and water systems.
Fossil fuel combustion, which produces sulphur dioxide, is used to generate electricity, heat homes and power vehicles. In Alberta, natural gas processing plants are responsible for close to half of the sulphur dioxide emissions in the province. Oil sands facilities and power plants are also major sources. Others include gas plant flares, oil refineries, pulp and paper mills and fertilizer plants.
More information on the environmental effects of sulphur dioxide is available on the Alberta Environment website.
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What actions are being taken?
The Province of Alberta is being proactive in the case of acid deposition strategy - establishing critical/target loads for acid deposition before any adverse environmental effects are observed. In 1997, the Acidifying Emissions Management Team was formed to work on critical and target loads for acid deposition in Alberta. See the CASA website for the Acidifying Emissions Management Team final report (2002).
In Alberta, acidifying emissions are managed under the Acid Deposition Management Framework. This framework is based on four levels of acid deposition, each corresponding to specific actions, or management practices. An updated report on sulphur dioxide emissions is prepared and evaluated every five years to ensure that Alberta's targets are met. The 2004 acid deposition assessment was completed in 2006 and the final report and recommendations are available from Alberta Environment’s Acid Deposition Management website. Included in the 2004 assessment was a review of the Acid Deposition Management Framework and the addition of regional applications. The next acid deposition assessment will begin in 2009.
Alberta has three Air Quality Objectives for sulphur dioxide: a one-hour objective of 172 parts per billion (ppb), a 24-hour objective of 57 parts per billion, and a mean annual objective of 11 parts per billion.
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Links to additional information
More information on sulphur dioxide monitoring: http://www.casadata.org/pollutants/sulphur_dioxide.asp
Sulphur Dioxide: Environmental Effects, Fate and Behaviour (report): http://www.environment.alberta.ca/3062.html
Assessment Report on Sulphur Dioxide for Developing Ambient Air Quality Objectives: Effects on Vegetation (report): http://www.environment.alberta.ca/3063.html
Focus on Acid Deposition: http://www.environment.gov.ab.ca/info/library/6193.pdf (PDF)
Acid Deposition Management Framework: http://environment.alberta.ca/1061.html
CASA Acidifying Emissions Management Team: http://www.casahome.org/?page_id=233
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Feedback
E-mail the SOE Coordinator: SOE.Coordinator@gov.ab.ca or complete this short on-line questionnaire to provide your feedback: http://www.zoomerang.com/
survey.zgi?p=WEB224DW6P3E2K.
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